Sorry, looks like I typed more but it didn't go through, odd. This happened when I was trying to change the resolution in Screen preferences, and it only appears in the syslog. Screen preferences just pops up a dialog saying "General system error". It was 100% reproducible trying to switch to any screen resolution until I rebooted, and then it worked normally again. However, I should note that the boot before this one had stuck on the rocket icon (#12237) which may have some how affected this.